1. Field of the Invention
This invention relates to a method for road surfacing wherein a hydrocarbon binder in the form of a foam is employed.
2. Description of the Prior Art
Road surface coatings with which the present invention is concerned are thin coatings which generally have no reinforcing effect on the roadways but which form idling surfaces either on roadways which are already coated and which require maintenance or on new roadways on which they form the surface layer.
It has heretofore been known to provide such coatings on the roadway to be surfaced with a layer of bituminous binder, on which is deposited a specified quantity of chippings (composed of suitably graded inorganic particles). If desired, a number of superimposed layers of such surfacings may be deposited. The binder layer is conventionally employed in quantities of from 0.75 to 2.50 kg. of binder per square meter, substantially corresponding to binder thickness of 0.75 to 2.50 mm. Graded products are employed in the case of chippings characterized by a particle size such that they pass through a screen of mesh dimension D (mm.) and do not pass through a screen of mesh dimension d (mm.) with d/D generally being 4/6, 6/10 or 10/14.
In spite of the precise standards and special precautions taken for deposition of the above road surfaces, the technique employed has encountered difficulty in application with consequent frequent failures. The latter have lead to serious consequences for road users since inadequate adhesion of the chippings by the binder causes the chippings to become unstuck and to be projected by the traffic leading to dangerous driving conditions which in turn are the cause of damage to vehicles using the roadway including broken windshields and the like. This problem of user safety is rendered more significant by the trend towards increased use of such surfacings on high speed roadways, due to the exceptional roughness of these surfaces.